Suction controls are routinely used in hospitals to regulate the level of suction delivered from a central supply system to the patient. Patient safety requires the high vacuum from the central supply be regulated to a lower safe level and adjustable for any number of clinical needs. On its most basic level, suction is used to remove fluids and debris from body cavities and is employed in virtually any location where a patient is present. Modern hospitals employ central suction systems with distributed supply at the patient bed. Mechanical controls reduce the high vacuum levels present in the central suction system to lower levels safe for patients and suitable for the patient collection devices. Collection devices are typically plastic, disposable devices that are used to accumulate fluids and debris. The collection devices are located between the point of collection and the control device and serve to protect the piping system and manual controls from contamination by bodily substances.
The manual controls that interface high vacuum in the central suction system with the patient contact collection systems are typically reusable, mechanical devices. The construction of these devices makes them prone to retention of fluids that may harbor infectious agents. Unlike other fluidic systems in the hospital, such as oxygen, nitrogen, or medical air, the inlet to the suction system is proximal to the patient and may not be filtered. In addition to room air, caregivers unintentionally introduce foreign material into the flow paths of these devices. The devices also contribute to contact vectors for contamination.
A complete fluid aspiration device consists of a control or regulator that attaches to the hospital central suction system, e.g., a system for providing partial vacuum at a desired level, for applying safe levels of suction pressure, collection devices for the accumulation of fluids and air separation, tubing and patient contact items, such as a catheter or a collection wand.
Suction controls may require a safety mechanism that is unique to the clinical application. For example, gastric drainage typically employs an intermitting cycling of the suction pressure to guard against continual application of suction to the interior of the gastric space which could result in traumatic lesions and possibly bleeding. In particular, in evacuating fluids from the stomach area it is possible for the suction catheter to engage the stomach wall, thereby occluding the inlet of the suction catheter. In such event, it is desirable to have the vacuum draw of fluid from the stomach become discontinuous, to free the catheter from sucking against the stomach wall and damaging the stomach lining. It is also common for debris in the stomach area to occlude the inlet ports of a catheter and thereby restrict or impede fluid flow. Periodic and regular relief of suction pressure to atmosphere will discourage debris accumulation on catheter inlets. Because it is not always readily apparent when such occlusion occurs, suction regulators can be operated on a substantially ongoing or intermittent manner by periodic regular cycling of vacuum on and venting to atmosphere of the collection circuit. In other instances, intermittent regulators are provided that may be set to operate in either a continuously intermittent (on/off, on/off, on/off, etc.) mode, or may be capable of being set to optionally operate in a constant-on or in a constant-off mode. It is also known that because of the nature of fluids being withdrawn from the body of a patient, it is necessary to provide regulators that are capable of being sterilized between uses.
In U.S. Pat. No. 6,228,056, whose disclosure is specifically incorporated by reference herein, and which is assigned to Boehringer Laboratories, Inc., the same assignee as the subject invention, there is disclosed and claimed an intermittent suction regulator, which is among other things particularly suited for gastric evacuation applications. That regulator includes a control mechanism for controlling the intermittent time cycle, with the control mechanism being isolated from the body fluids that are delivered to the regulator from the body of the patient.
Boehringer Laboratories, Inc. offers various suction regulators, some of which are constructed in accordance with its aforementioned patent. Those commercially available regulators also have three modes of operation. Those modes are: the “OFF” mode; the “CONTINUOUS” mode; and the “INTERMITTENT” mode. In the “OFF” mode the line that is coupled to the patient is isolated from the hospital's suction line and is thus at the ambient atmospheric pressure. In the “CONTINUOUS” mode the line that is coupled to the patient is at a regulated level of suction (e.g., 200 mm Hg.) that is provided continuously and is below the level of suction (e.g., 600 mm Hg.) provided by the hospital's suction line. In the “INTERMITTENT” mode the line that is coupled to the patient is at a regulated level of suction (e.g., 200 mm Hg.) but is provided intermittently, e.g., 16-20 seconds “on” and 8-10 seconds “off”.
While the intermittent regulators of the foregoing patents and those commercially available from Boehringer Laboratories, Inc. are eminently suitable for their intended purposes the never-the-less leaves something to be desired from the standpoint of functionality. In particular, for some applications, it may be desirable to enable the suction regulator to apply the full suction available on the hospital's suction line, e.g., 600 mm Hg., to the line to the patient. For example, if a device which is connected in the patient's suction line should become clogged, it may be desired to apply the full suction to that line to clear the device. Accordingly, a need exists for an intermittent suction regulator which also provides a mode of operation in which the full vacuum provided at the hospital's suction line is coupled to the patient's line. The subject invention addresses that need. In addition, hospitals and other similar institutions often desire standardization. Thus a suction regulator that satisfies all clinical needs would be welcome addition. The subject invention addresses that need as well.